1. Field of the Invention
This invention relates to periscopes and more especially to portable periscopes such as commonly used by persons in crowds desiring to look over the intervening heads of persons in the crowd at a parade, exhibition, tournament and the like. This invention is more particularly concerned with a periscope which is capable of being folded into a flat structure which is dimensionally small enough to be carried in a user's pocket prior to and after use with a minimum of disassembly.
2. Description of the Prior Art
Many sports enthusiasts prefer to go to a baseball, football or other game in person in order to enjoy the sights and sounds of a live event and to feel the excitement of the crowd. For many other and similar reasons, many people also like to go to parades or other exhibitions where they are part of a large crowd watching a particular event. However, observers who are part of a crowd at such events may have difficulty viewing the event due to the viewing obstructions of intervening heads. Many observers may become exasperated from craning their necks for a long time trying to get a good view of the event.
In order to allow people to enjoy watching such events, many types of periscopes have been marketed. Basically, such prior art periscopes have provided a certain degree of portability and have been of three basic types: foldable cardboard periscopes, telescopic periscopes and dual purpose periscopes.
An example of a foldable cardboard prior art periscope is disclosed in U.S. Pat. No. 3,357,777 to Kallio. The Kallio periscope is composed of a one piece body composed of cardboard or fiberboard having fold lines at specific locations thereon. The fold lines partially define the boundaries of body sections with a front section being offset longitudinally with a back section. This offset relationship allows mirrors to be mounted at opposing ends of the sections and parallel to each other when the body is folded along the fold lines to form a periscope frame. The body is secured together by means of a suitable adhesive so that the periscope is permanently formed. Detaching certain interlocking members of the body allows the body to be collapsed into a generally flat structure. Another example of a prior art foldable cardboard periscope is disclosed in U.S. Pat. No. 2,155,164 to Harris. The Harris periscope is similar to the Kallio periscope except that it has viewing peepholes and is provided with wings having shoulders to position the mirrors at the desired angle of inclination with respect to the main body. However, a primary disadvantage with such prior art periscopes is that when collapsed such periscopes are at their full length (in fact, they are even longer than when erect) and therefore cannot be carried in a person's pocket or purse. Thus, such prior art periscopes have only a very limited degree of portability.
An example of both a telescopic and dual purpose prior art periscope is disclosed in U.S. Pat. No. 3,014,408 to Miller. The Miller periscope is essentially composed of an inner and an outer sleeve. The inner sleeve contains the food or other suitable material. When filled with the food, the inner sleeve is slidably inserted into the open end of the outer sleeve. A flap retains the inner sleeve in the desired position within the outer sleeve. The flap also holds one of the mirrors. Although this prior art periscope has the advantage of being both a container as well as a periscope, its major disadvantage is that even in collapsed form it is nevertheless a rather bulky box type structure and thus not very convenient to carry. Moreover, the necessity of having the inner sleeve slidable within the outer sleeve and the sleeves having a close tolerance fit results in a relatively expensive periscope to manufacture.
A portable periscope is thus needed that will allow the user to conveniently carry the periscope on his person or in his pocket and which is relatively inexpensive to manufacture and which can be easily deployed by the user.